The present invention relates to control apparatus and method for an automatic transmission adapted to transmit power by selectively engaging a friction clutch (or friction-engagement element).
Generally when carrying out a shift of automatic transmission (when changing a speed-step), a friction-engagement element such as a clutch is changed from a disengaged state to an engaged state, or changed from the engaged state to the disengaged state. In such case, it is desired that an operation for the friction-engagement element is performed smoothly and quickly so as not to generate a shock at the time of shift. Japanese Published Patent Application No. 1997(H09)-170654 discloses a previously proposed control apparatus. In this technique, hydraulic pressure to a hydraulic servo of friction-engagement element is adjusted in order to reduce the shock generated at the time of shift.